In recent years, a facet search is used as an information search mechanism. The facet search is a mechanism that navigates a user on a facet (aspect of things) as a condition for an information search and sends back an information search result to an arbitrary facet selected by the user.
The facet-type metadata is basically constituted of relationships among categories and facet values. Specifically, by structuring the facet values to have a hierarchical relationship with lower-order facet values, the facet-type data can be hierarchized.
For example, when there are “place” and “time” as categories of a top hierarchy, “Western Europe”, “Asia”, “North America”, or the like that largely categorizes the place is defined as a facet value corresponding to the category “place”. This facet value belongs to a category of a subsequent lower-order hierarchy, and “Japan”, “Korea”, “Taiwan”, or the like is defined as a facet value corresponding to the category “Asia”, for example. Also in the case of the category “time”, the relationships among the categories and facet values are defined hierarchically. Prior to the search, the user can select one or more conditions narrowed down based on the hierarchical relationships among the categories and facet values and the hierarchical relationships among the facet values in the facet-type data.
Patent Document 1 discloses a server apparatus that includes a storage section for storing facet-type data in which priorities are set to facet items (categories) to narrow down content-related information (advertisement information and product information) using the facet-type data and sends back a content selected by a user and related information of the selected content, that is based on the facet items and facet values, to the user.
Patent Document 1: Japanese Patent Application Laid-open No. 2011-107908